A JSATURAL PUZZLE 227 



waters, the Ckeraphilus eahinulentiis of Michael Sars, 

 and Gheraphilus negledus, G. 0. Sars. The last-named 

 author, however, has quite recently been able to make 

 a very unexpected contribution to the settlement of the 

 question, for, in examining the development of diflferent 

 members of the family, he has found that the various 

 genera and species are often more strongly distinguished 

 in the larval forms than in the adults, so that the 

 hesitation felt about separating, for example, the species 

 Crangon vulgaris and Grangon AUmanni, or the genera 

 Gheraphilus and Pontopldlus, can no longer reasonably be 

 persisted in. Gheraphilus, it may be mentioned, agrees 

 with Grangon in having five pairs of branchiae attached 

 respectively to the five pairs of trunk-legs, but Pontophilus, 

 while agreeing with Gheraphilus in the shortness of the 

 second legs, differs both from it and Grangon in having six 

 pairs of well-developed branchiaa, besides a rudimentary 

 pair on the second maxillipeds. Since the species Egeon 

 fasciatus, Eisso, has been providied by nature with a re- 

 markable brown band across the fourth segment of the 

 . pleon and similar colouring on the tail-fan, as if to sepa- 

 rate it unmistakably from all other species, and to enable 

 the collector to identify it without further trouble, it may 

 be well to notice that Gheraphilus negledus also has a deep 

 brown band across the fourth segment of the pleon and a 

 narrower one across the tail-fan, so that after all the col- 

 lector has need to be cautious. 



The arctic Sabinea septemca/rinata (Sabine) agrees with 

 Pontophilus in the branchial formula. In describing it in 

 1821 Sabine calls attention to the fact that the second legs 

 are ' unarmed,' that is, simple or not chelate, and, while 

 recognising that this is an ' essential point ' of distinction 

 from the known species of Grangon and Pontophilus, he 

 enters one of the common but always useless protests 

 against the multiplication of genera. If he spoke thus in 

 1821, what would he have thought in 1891 ? Kroyer, 

 who redescribed the species in 1812, after stating that it 

 is very abundant at Spitzbergen, adds that he had found 

 the stomach of the seal Phoca harbata quite filled with it. 

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